--- rat/lonuserstate.pm 2008/12/21 04:46:53 1.128.2.1 +++ rat/lonuserstate.pm 2011/08/04 10:57:26 1.139 @@ -1,7 +1,7 @@ # The LearningOnline Network with CAPA # Construct and maintain state and binary representation of course for user # -# $Id: lonuserstate.pm,v 1.128.2.1 2008/12/21 04:46:53 raeburn Exp $ +# $Id: lonuserstate.pm,v 1.139 2011/08/04 10:57:26 foxr Exp $ # # Copyright Michigan State University Board of Trustees # @@ -43,11 +43,13 @@ use Opcode; use Apache::lonenc; use Fcntl qw(:flock); use LONCAPA; +use File::Basename; + # ---------------------------------------------------- Globals for this package -my $pc; # Package counter +my $pc; # Package counter is this what 'Guts' calls the map counter? my %hash; # The big tied hash my %parmhash;# The hash with the parameters my @cond; # Array with all of the conditions @@ -62,6 +64,27 @@ my %hiddenurl; # this URL (or complete f # ----------------------------------- Remove version from URL and store in hash +sub versionerror { + my ($uri,$usedversion,$unusedversion)=@_; + return '
'.&mt('Version discrepancy: resource [_1] included in both version [_2] and version [_3]. Using version [_2].', + $uri,$usedversion,$unusedversion).'
'; +} + +# Removes the version number from a URI and returns the resulting +# URI (e.g. mumbly.version.stuff => mumbly.stuff). +# +# If the URI has not been seen with a versio before the +# hash{'version_'.resultingURI} is set to the version number. +# If the URI has been seen and the version does not match and error +# is added to the error string. +# +# Parameters: +# URI potentially with a version. +# Returns: +# URI with the version cut out. +# See above for side effects. +# + sub versiontrack { my $uri=shift; if ($uri=~/\.(\d+)\.\w+$/) { @@ -69,7 +92,9 @@ sub versiontrack { $uri=~s/\.\d+\.(\w+)$/\.$1/; unless ($hash{'version_'.$uri}) { $hash{'version_'.$uri}=$version; - } + } elsif ($version!=$hash{'version_'.$uri}) { + $errtext.=&versionerror($uri,$hash{'version_'.$uri},$version); + } } return $uri; } @@ -104,32 +129,55 @@ sub processversionfile { } } -# --------------------------------------------------------- Loads map from disk +# --------------------------------------------------------- Loads from disk sub loadmap { my ($uri,$parent_rid)=@_; + + # Is the map already included? + if ($hash{'map_pc_'.$uri}) { $errtext.='

'. &mt('Multiple use of sequence/page [_1]! The course will not function properly.',''.$uri.''). '

'; return; } + # Register the resource in it's map_pc_ [for the URL] + # map_id.nnn is the nesting level -> to the URI. + $pc++; my $lpc=$pc; $hash{'map_pc_'.$uri}=$lpc; $hash{'map_id_'.$lpc}=$uri; -# Determine and check filename + # If the parent is of the form n.m hang this map underneath it in the + # map hierarchy. + + if ($parent_rid =~ /^(\d+)\.\d+$/) { + my $parent_pc = $1; + if (defined($hash{'map_hierarchy_'.$parent_pc})) { + $hash{'map_hierarchy_'.$lpc}=$hash{'map_hierarchy_'.$parent_pc}.','. + $parent_pc; + } else { + $hash{'map_hierarchy_'.$lpc}=$parent_pc; + } + } + +# Determine and check filename of the sequence we need to read: + my $fn=&Apache::lonnet::filelocation('',&putinversion($uri)); my $ispage=($fn=~/\.page$/); - unless (($fn=~/\.sequence$/) || - ($fn=~/\.page$/)) { + # We can only nest sequences or pages. Anything else is an illegal nest. + + unless (($fn=~/\.sequence$/) || $ispage) { $errtext.=&mt("
Invalid map: [_1]",$fn); return; } + # Read the XML that constitutes the file. + my $instr=&Apache::lonnet::getfile($fn); if ($instr eq -1) { @@ -137,18 +185,29 @@ sub loadmap { return; } -# Successfully got file, parse it + # Successfully got file, parse it + + # parse for parameter processing. + # Note that these are tags + # so we only care about 'S' (tag start) nodes. + my $parser = HTML::TokeParser->new(\$instr); $parser->attr_encoded(1); + # first get all parameters + + while (my $token = $parser->get_token) { next if ($token->[0] ne 'S'); if ($token->[1] eq 'param') { &parse_param($token,$lpc); } } - #reset parser + + # Get set to take another pass through the XML: + # for resources and links. + $parser = HTML::TokeParser->new(\$instr); $parser->attr_encoded(1); @@ -160,27 +219,54 @@ sub loadmap { my $randomize = ($randomorder{$parent_rid} =~ /^yes$/i); + # Parse the resources, link and condition tags. + # Note that if randomorder or random select is chosen the links and + # conditions are meaningless but are determined by the randomization. + # This is handled in the next chunk of code. + my @map_ids; while (my $token = $parser->get_token) { next if ($token->[0] ne 'S'); + + # Resource + if ($token->[1] eq 'resource') { - push(@map_ids,&parse_resource($token,$lpc,$ispage,$uri)); + my $resource_id = &parse_resource($token,$lpc,$ispage,$uri); + if (defined $resource_id) { + push(@map_ids, $resource_id); + } + + # Link + } elsif ($token->[1] eq 'link' && !$randomize) { -# ----------------------------------------------------------------------- Links &make_link(++$linkpc,$lpc,$token->[2]->{'to'}, $token->[2]->{'from'}, - $token->[2]->{'condition'}); + $token->[2]->{'condition'}); # note ..condition may be undefined. + + # condition + } elsif ($token->[1] eq 'condition' && !$randomize) { &parse_condition($token,$lpc); } } + + # Handle randomization and random selection + if ($randomize) { if (!$env{'request.role.adv'}) { my $seed; + + # In the advanced role, the map's random seed + # parameter is used as the basis for computing the + # seed ... if it has been specified: + if (defined($randompickseed{$parent_rid})) { $seed = $randompickseed{$parent_rid}; } else { + + # Otherwise the parent's fully encoded symb is used. + my ($mapid,$resid)=split(/\./,$parent_rid); my $symb= &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid}, @@ -188,16 +274,27 @@ sub loadmap { $seed = $symb; } - + + # TODO: Here for sure we need to pass along the username/domain + # so that we can impersonate users in lonprintout e.g. + my $rndseed=&Apache::lonnet::rndseed($seed); &Apache::lonnet::setup_random_from_rndseed($rndseed); - @map_ids=&Math::Random::random_permutation(@map_ids); + @map_ids=&math::Random::random_permutation(@map_ids); # randomorder. } + + my $from = shift(@map_ids); my $from_rid = $lpc.'.'.$from; $hash{'map_start_'.$uri} = $from_rid; $hash{'type_'.$from_rid}='start'; + # Create links to reflect this random ordering. + # BUG? If there are conditions, this invalidates them? Then again + # with randompick there's no gaurentee the resources required for the + # conditinos to work will be selected into the map. + # so randompick is inconsistent with a map that has conditions? + while (my $to = shift(@map_ids)) { &make_link(++$linkpc,$lpc,$to,$from); my $to_rid = $lpc.'.'.$to; @@ -212,8 +309,10 @@ sub loadmap { $parser = HTML::TokeParser->new(\$instr); $parser->attr_encoded(1); + # last parse out the mapalias params so as to ignore anything # refering to non-existant resources + while (my $token = $parser->get_token) { next if ($token->[0] ne 'S'); if ($token->[1] eq 'param') { @@ -224,25 +323,89 @@ sub loadmap { # -------------------------------------------------------------------- Resource +# +# Parses a resource tag to produce the value to push into the +# map_ids array. +# +# +# Information about the actual type of resource is provided by the file extension +# of the uri (e.g. .problem, .sequence etc. etc.). +# +# Parameters: +# $token - A token from HTML::TokeParser +# This is an array that describes the most recently parsed HTML item. +# $lpc - Map nesting level (?) +# $ispage - True if this resource is encapsulated in a .page (assembled resourcde). +# $uri - URI of the enclosing resource. +# Returns: +# Value of the id attribute of the tag. +# +# Note: +# The token is an array that contains the following elements: +# [0] => 'S' indicating this is a start token +# [1] => 'resource' indicating this tag is a tag. +# [2] => Hash of attribute =>value pairs. +# [3] => @(keys [2]). +# [4] => unused. +# +# The attributes of the resourcde tag include: +# +# id - The resource id. +# src - The URI of the resource. +# type - The resource type (e.g. start and finish). +# title - The resource title. + + sub parse_resource { my ($token,$lpc,$ispage,$uri) = @_; - if ($token->[2]->{'type'} eq 'zombie') { next; } - my $rid=$lpc.'.'.$token->[2]->{'id'}; + + # I refuse to countenance code like this that has + # such a dirty side effect (and forcing this sub to be called within a loop). + # + # if ($token->[2]->{'type'} eq 'zombie') { next; } + # + # The original code both returns _and_ skips to the next pass of the >caller's< + # loop, that's just dirty. + # + + # Zombie resources don't produce anything useful. + + if ($token->[2]->{'type'} eq 'zombie') { + return undef; + } + + my $rid=$lpc.'.'.$token->[2]->{'id'}; # Resource id in hash is levelcounter.id-in-xml. + + # Save the hash element type and title: $hash{'kind_'.$rid}='res'; $hash{'title_'.$rid}=$token->[2]->{'title'}; + + # Get the version free URI for the resource. + # If a 'version' attribute was supplied, and this resource's version + # information has not yet been stored, store it. + # + my $turi=&versiontrack($token->[2]->{'src'}); if ($token->[2]->{'version'}) { unless ($hash{'version_'.$turi}) { $hash{'version_'.$turi}=$1; } } + # Pull out the title and do entity substitution on &colon + # Q: Why no other entity substitutions? + my $title=$token->[2]->{'title'}; $title=~s/\&colon\;/\:/gs; -# my $symb=&Apache::lonnet::encode_symb($uri, -# $token->[2]->{'id'}, -# $turi); -# &Apache::lonnet::do_cache_new('title',$symb,$title); + + + + # I think the point of all this code is to construct a final + # URI that apache and its rewrite rules can use to + # fetch the resource. Thi s sonly necessary if the resource + # is not a page. If the resource is a page then it must be + # assembled (at fetch time?). + unless ($ispage) { $turi=~/\.(\w+)$/; my $embstyle=&Apache::loncommon::fileembstyle($1); @@ -269,7 +432,10 @@ sub parse_resource { } } } -# Store reverse lookup, remove query string + # Store reverse lookup, remove query string resource 'ids'_uri => resource id. + # If the URI appears more than one time in the sequence, it's resourcde + # id's are constructed as a comma spearated list. + my $idsuri=$turi; $idsuri=~s/\?.+$//; if (defined($hash{'ids_'.$idsuri})) { @@ -278,17 +444,37 @@ sub parse_resource { $hash{'ids_'.$idsuri}=''.$rid; } - if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard)$/) { + + + if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard|viewclasslist)$/) { $turi.='?register=1'; } + + # resource id lookup: 'src'_resourc-di => URI decorated with a query + # parameter as above if necessary due to the resource type. + $hash{'src_'.$rid}=$turi; + + # Mark the external-ness of the resource: if ($token->[2]->{'external'} eq 'true') { $hash{'ext_'.$rid}='true:'; } else { $hash{'ext_'.$rid}='false:'; } + + # If the resource is a start/finish resource set those + # entries in the has so that navigation knows where everything starts. + # TODO? If there is a malformed sequence that has no start or no finish + # resource, should this be detected and errors thrown? How would such a + # resource come into being other than being manually constructed by a person + # and then uploaded? Could that happen if an author decided a sequence was almost + # right edited it by hand and then reuploaded it to 'fix it' but accidently cut the + # start or finish resources? + # + # All resourcess also get a type_id => (start | finish | normal) hash entr. + # if ($token->[2]->{'type'}) { $hash{'type_'.$rid}=$token->[2]->{'type'}; if ($token->[2]->{'type'} eq 'start') { @@ -300,6 +486,12 @@ sub parse_resource { } else { $hash{'type_'.$rid}='normal'; } + + # Sequences end pages are constructed entities. They require that the + # map that defines _them_ be loaded as well into the hash...with this resourcde + # as the base of the nesting. + # Resources like that are also marked with is_map_id => 1 entries. + # if (($turi=~/\.sequence$/) || ($turi=~/\.page$/)) { @@ -309,22 +501,65 @@ sub parse_resource { return $token->[2]->{'id'}; } +#-------------------------------------------------------------------- link +# Links define how you are allowed to move from one resource to another. +# They are the transition edges in the directed graph that a map is. +# This sub takes informatino from a tag and constructs the +# navigation bits and pieces of a map. There is no requirement that the +# resources that are linke are already defined, however clearly the map is +# badly broken if they are not _eventually_ defined. +# +# Note that links can be unconditional or conditional. +# +# Parameters: +# linkpc - The link counter for this level of map nesting (this is +# reset to zero by loadmap prior to starting to process +# links for map). +# lpc - The map level ocounter (how deeply nested this map is in +# the hierarchy of maps that are recursively read in. +# to - resource id (within the XML) of the target of the edge. +# from - resource id (within the XML) of the source of the edge. +# condition- id of condition associated with the edge (also within the XML). +# + sub make_link { my ($linkpc,$lpc,$to,$from,$condition) = @_; + # Compute fully qualified ids for the link, the + # and from/to by prepending lpc. + # + my $linkid=$lpc.'.'.$linkpc; my $goesto=$lpc.'.'.$to; my $comesfrom=$lpc.'.'.$from; my $undercond=0; + + # If there is a condition, qualify it with the level counter. + if ($condition) { $undercond=$lpc.'.'.$condition; } + # Links are represnted by: + # goesto_.fuullyqualifedlinkid => fully qualified to + # comesfrom.fullyqualifiedlinkid => fully qualified from + # undercond_.fullyqualifiedlinkid => fully qualified condition id. + $hash{'goesto_'.$linkid}=$goesto; $hash{'comesfrom_'.$linkid}=$comesfrom; $hash{'undercond_'.$linkid}=$undercond; + # In addition: + # to_.fully qualified from => comma separated list of + # link ids with that from. + # Similarly: + # from_.fully qualified to => comma separated list of link ids` + # with that to. + # That allows us given a resource id to know all edges that go to it + # and leave from it. + # + if (defined($hash{'to_'.$comesfrom})) { $hash{'to_'.$comesfrom}.=','.$linkid; } else { @@ -338,6 +573,54 @@ sub make_link { } # ------------------------------------------------------------------- Condition +# +# Processes tags, storing sufficient information about them +# in the hash so that they can be evaluated and used to conditionalize +# what is presented to the student. +# +# these can have the following attributes +# +# id = A unique identifier of the condition within the map. +# +# value = Is a perl script-let that, when evaluated in safe space +# determines whether or not the condition is true. +# Normally this takes the form of a test on an Apache::lonnet::EXT call +# to find the value of variable associated with a resource in the +# map identified by a mapalias. +# Here's a fragment of XML code that illustrates this: +# +# +# +# +# +# +# +# In this fragment: +# - The param tag establishes an alias to resource id 5 of 'mainproblem'. +# - The resource that is the start of the map is identified. +# - The resource tag identifies the resource associated with this tag +# and gives it the id 5. +# - The condition is true if the tries variable associated with mainproblem +# is less than 2 (that is the user has had more than 2 tries). +# The condition type is a stop condition which inhibits(?) the associated +# link if the condition is false. +# - The link to resource 5 from resource 1 is affected by this condition. +# +# type = Type of the condition. The type determines how the condition affects the +# link associated with it and is one of +# - 'force' +# - 'stop' +# anything else including not supplied..which treated as: +# - 'normal'. +# Presumably maps get created by the resource assembly tool and therefore +# illegal type values won't squirm their way into the XML. +# +# Side effects: +# - The kind_level-qualified-condition-id hash element is set to 'cond'. +# - The condition text is pushed into the cond array and its element number is +# set in the condid_level-qualified-condition-id element of the hash. +# - The condition type is colon appneded to the cond array element for this condition. sub parse_condition { my ($token,$lpc) = @_; my $rid=$lpc.'.'.$token->[2]->{'id'}; @@ -356,36 +639,77 @@ sub parse_condition { } # ------------------------------------------------------------------- Parameter +# Parse a tag in the map. +# Parmameters: +# $token Token array for a start tag from HTML::TokeParser +# [0] = 'S' +# [1] = tagname ("param") +# [2] = Hash of {attribute} = values. +# [3] = Array of the keys in [2]. +# [4] = unused. +# $lpc Current map nesting level.a +# +# Typical attributes: +# to=n - Number of the resource the parameter applies to. +# type=xx - Type of parameter value (e.g. string_yesno or int_pos). +# name=xxx - Name ofr parameter (e.g. parameter_randompick or parameter_randomorder). +# value=xxx - value of the parameter. sub parse_param { my ($token,$lpc) = @_; - my $referid=$lpc.'.'.$token->[2]->{'to'}; - my $name=$token->[2]->{'name'}; + my $referid=$lpc.'.'.$token->[2]->{'to'}; # Resource param applies to. + my $name=$token->[2]->{'name'}; # Name of parameter my $part; - if ($name=~/^parameter_(.*)_/) { + + + if ($name=~/^parameter_(.*)_/) { $part=$1; } else { $part=0; } + + # Peel the parameter_ off the parameter name. + $name=~s/^.*_([^_]*)$/$1/; + + # The value is: + # type.part.name.value + my $newparam= &escape($token->[2]->{'type'}).':'. &escape($part.'.'.$name).'='. &escape($token->[2]->{'value'}); + + # The hash key is param_resourceid. + # Multiple parameters for a single resource are & separated in the hash. + + if (defined($hash{'param_'.$referid})) { $hash{'param_'.$referid}.='&'.$newparam; } else { $hash{'param_'.$referid}=''.$newparam; } - if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) { + # + # These parameters have to do with randomly selecting + # resources, therefore a separate hash is also created to + # make it easy to locate them when actually computing the resource set later on + # See the code conditionalized by ($randomize) in loadmap(). + + if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) { # Random selection turned on $randompick{$referid}=$token->[2]->{'value'}; } - if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) { + if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) { # Randomseed provided. $randompickseed{$referid}=$token->[2]->{'value'}; } - if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) { + if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) { # Random order turned on. $randomorder{$referid}=$token->[2]->{'value'}; } + + # These parameters have to do with how the URLs of resources are presented to + # course members(?). encrypturl presents encypted url's while + # hiddenresource hides the URL. + # + if ($token->[2]->{'name'}=~/^parameter_(0_)*encrypturl$/) { if ($token->[2]->{'value'}=~/^yes$/i) { $encurl{$referid}=1; @@ -573,7 +897,8 @@ sub accinit { $acchash{'acc.res.'.$short.'.'}='&:0&'; my $courseuri=$uri; $courseuri=~s/^\/res\///; - &Apache::lonnet::delenv('(acc\.|httpref\.)'); + my $regexp = 1; + &Apache::lonnet::delenv('(acc\.|httpref\.)',$regexp); &Apache::lonnet::appenv(\%acchash); } @@ -639,135 +964,229 @@ sub hiddenurls { sub readmap { my $short=shift; $short=~s/^\///; - my %cenv=&Apache::lonnet::coursedescription($short,{'freshen_cache'=>1}); + + # TODO: Hidden dependency on current user: + + my %cenv=&Apache::lonnet::coursedescription($short,{'freshen_cache'=>1}); + my $fn=$cenv{'fn'}; my $uri; $short=~s/\//\_/g; unless ($uri=$cenv{'url'}) { - &Apache::lonnet::logthis("WARNING: ". + &Apache::lonnet::logthis('WARNING: '. "Could not load course $short."); return ('',&mt('No course data available.'));; } @cond=('true:normal'); - open(LOCKFILE,">$fn.db.lock"); + unless (open(LOCKFILE,">$fn.db.lock")) { + # + # Most likely a permissions problem on the lockfile or its directory. + # + $errtext.='
'.&mt('Map not loaded - Lock file could not be opened when reading map:').' '.$fn.'.'; + $retfurl = ''; + return ($retfurl,$errtext); + } my $lock=0; - if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) { - $lock=1; - unlink($fn.'.db'); - unlink($fn.'_symb.db'); - unlink($fn.'.state'); - unlink($fn.'parms.db'); + my $gotstate=0; + + # If we can get the lock without delay any files there are idle + # and from some prior request. We'll kill them off and regenerate them: + + if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) { + $lock=1; # Remember that we hold the lock. + &unlink_tmpfiles($fn); } undef %randompick; undef %hiddenurl; undef %encurl; $retfrid=''; - if ($lock && (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) && - (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640))) { - %hash=(); - %parmhash=(); - $errtext=''; - $pc=0; - &clear_mapalias_count(); - &processversionfile(%cenv); - my $furi=&Apache::lonnet::clutter($uri); - $hash{'src_0.0'}=&versiontrack($furi); - $hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title'); - $hash{'ids_'.$furi}='0.0'; - $hash{'is_map_0.0'}=1; - loadmap($uri,'0.0'); - if (defined($hash{'map_start_'.$uri})) { - &Apache::lonnet::appenv({"request.course.id" => $short, - "request.course.fn" => $fn, - "request.course.uri" => $uri}); - $env{'request.course.id'}=$short; - &traceroute('0',$hash{'map_start_'.$uri},'&'); - &accinit($uri,$short,$fn); - &hiddenurls(); - } - $errtext .= &get_mapalias_errors(); -# ------------------------------------------------------- Put versions into src - foreach my $key (keys(%hash)) { - if ($key=~/^src_/) { - $hash{$key}=&putinversion($hash{$key}); - } elsif ($key =~ /^(map_(?:start|finish|pc)_)(.*)/) { - my ($type, $url) = ($1,$2); - my $value = $hash{$key}; - $hash{$type.&putinversion($url)}=$value; - } - } -# ---------------------------------------------------------------- Encrypt URLs - foreach my $id (keys(%encurl)) { -# $hash{'src_'.$id}=&Apache::lonenc::encrypted($hash{'src_'.$id}); - $hash{'encrypted_'.$id}=1; - } -# ----------------------------------------------- Close hashes to finally store -# --------------------------------- Routine must pass this point, no early outs - $hash{'first_rid'}=$retfrid; - my ($mapid,$resid)=split(/\./,$retfrid); - $hash{'first_mapurl'}=$hash{'map_id_'.$mapid}; - my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$hash{'src_'.$retfrid}); - $retfurl=&add_get_param($hash{'src_'.$retfrid},{ 'symb' => $symb }); - if ($hash{'encrypted_'.$retfrid}) { - $retfurl=&Apache::lonenc::encrypted($retfurl,(&Apache::lonnet::allowed('adv') ne 'F')); - } - $hash{'first_url'}=$retfurl; - unless ((untie(%hash)) && (untie(%parmhash))) { - &Apache::lonnet::logthis("WARNING: ". - "Could not untie coursemap $fn for $uri."); - } -# ---------------------------------------------------- Store away initial state - { - my $cfh; - if (open($cfh,">$fn.state")) { - print $cfh join("\n",@cond); - } else { - &Apache::lonnet::logthis("WARNING: ". - "Could not write statemap $fn for $uri."); - } - } - flock(LOCKFILE,LOCK_UN); - close(LOCKFILE); - } else { + my ($untiedhash,$untiedparmhash,$tiedhash,$tiedparmhash); # More state flags. + + # if we got the lock, regenerate course regnerate empty files and tie them. + + if ($lock) { + if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) { + $tiedhash = 1; + if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640)) { + $tiedparmhash = 1; + $gotstate = &build_tmp_hashes($uri, + $fn, + $short, + \%cenv); # TODO: Need to provide requested user@dom + unless ($gotstate) { + &Apache::lonnet::logthis('Failed to write statemap at first attempt '.$fn.' for '.$uri.'.'); + } + $untiedparmhash = untie(%parmhash); + unless ($untiedparmhash) { + &Apache::lonnet::logthis('WARNING: '. + 'Could not untie coursemap parmhash '.$fn.' for '.$uri.'.'); + } + } + $untiedhash = untie(%hash); + unless ($untiedhash) { + &Apache::lonnet::logthis('WARNING: '. + 'Could not untie coursemap hash '.$fn.' for '.$uri.'.'); + } + } + flock(LOCKFILE,LOCK_UN); # RF: this is what I don't get unless there are other + # unlocked places the remainder happens..seems like if we + # just kept the lock here the rest of the code would have + # been much easier? + } + unless ($lock && $tiedhash && $tiedparmhash) { # if we are here it is likely because we are already trying to # initialize the course in another child, busy wait trying to # tie the hashes for the next 90 seconds, if we succeed forward # them on to navmaps, if we fail, throw up the Could not init # course screen + # + # RF: I'm not seeing the case where the ties/unties can fail in a way + # that can be remedied by this. Since we owned the lock seems + # Tie/untie failures are a result of something like a permissions problem instead? + # + + # In any vent, undo what we did manage to do above first: if ($lock) { # Got the lock but not the DB files flock(LOCKFILE,LOCK_UN); + $lock = 0; } - untie(%hash); - untie(%parmhash); - &Apache::lonnet::logthis("WARNING: ". - "Could not tie coursemap $fn for $uri."); + if ($tiedhash) { + unless($untiedhash) { + untie(%hash); + } + } + if ($tiedparmhash) { + unless($untiedparmhash) { + untie(%parmhash); + } + } + # Log our failure: + + &Apache::lonnet::logthis('WARNING: '. + "Could not tie coursemap $fn for $uri."); + $tiedhash = ''; + $tiedparmhash = ''; my $i=0; + + # Keep on retrying the lock for 90 sec until we succeed. + while($i<90) { $i++; sleep(1); - if (flock(LOCKFILE,LOCK_EX|LOCK_NB) && - (tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640))) { - if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_READER(),0640)) { - $retfurl='/adm/navmaps'; - &Apache::lonnet::appenv({"request.course.id" => $short, - "request.course.fn" => $fn, - "request.course.uri" => $uri}); - untie(%hash); - untie(%parmhash); - last; - } - } - untie(%hash); - untie(%parmhash); + if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) { + + # Got the lock, tie the hashes...the assumption in this code is + # that some other worker thread has created the db files quite recently + # so no load is needed: + + $lock = 1; + if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640)) { + $tiedhash = 1; + if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_READER(),0640)) { + $tiedparmhash = 1; + if (-e "$fn.state") { + $retfurl='/adm/navmaps'; + + # BUG BUG: Side effect! + # Should conditionalize on something so that we can use this + # to load maps for courses that are not current? + # + &Apache::lonnet::appenv({"request.course.id" => $short, + "request.course.fn" => $fn, + "request.course.uri" => $uri}); + $untiedhash = untie(%hash); + $untiedparmhash = untie(%parmhash); + $gotstate = 1; + last; + } + $untiedparmhash = untie(%parmhash); + } + $untiedhash = untie(%hash); + } + } } - flock(LOCKFILE,LOCK_UN); - close(LOCKFILE); + if ($lock) { + flock(LOCKFILE,LOCK_UN); + $lock = 0; + if ($tiedparmhash) { + unless ($untiedparmhash) { + &Apache::lonnet::logthis('WARNING: '. + 'Could not untie coursemap parmhash '.$fn.' for '.$uri.'.'); + } + } + if ($tiedparmhash) { + unless ($untiedhash) { + &Apache::lonnet::logthis('WARNING: '. + 'Could not untie coursemap hash '.$fn.' for '.$uri.'.'); + } + } + } + } + # I think this branch of code is all about what happens if we just did the stuff above, + # but found that the state file did not exist...again if we'd just held the lock + # would that have made this logic simpler..as generating all the files would be + # an atomic operation with respect to the lock. + # + unless ($gotstate) { + $lock = 0; + &Apache::lonnet::logthis('WARNING: '. + 'Could not read statemap '.$fn.' for '.$uri.'.'); + &unlink_tmpfiles($fn); + if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) { + $lock=1; + } + undef %randompick; + undef %hiddenurl; + undef %encurl; + $retfrid=''; + # + # Once more through the routine of tying and loading and so on. + # + if ($lock) { + if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) { + if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640)) { + $gotstate = &build_tmp_hashes($uri,$fn,$short,\%cenv); # TODO: User dependent? + unless ($gotstate) { + &Apache::lonnet::logthis('WARNING: '. + 'Failed to write statemap at second attempt '.$fn.' for '.$uri.'.'); + } + unless (untie(%parmhash)) { + &Apache::lonnet::logthis('WARNING: '. + 'Could not untie coursemap parmhash '.$fn.'.db for '.$uri.'.'); + } + } else { + &Apache::lonnet::logthis('WARNING: '. + 'Could not tie coursemap '.$fn.'__parms.db for '.$uri.'.'); + } + unless (untie(%hash)) { + &Apache::lonnet::logthis('WARNING: '. + 'Could not untie coursemap hash '.$fn.'.db for '.$uri.'.'); + } + } else { + &Apache::lonnet::logthis('WARNING: '. + 'Could not tie coursemap '.$fn.'.db for '.$uri.'.'); + } + flock(LOCKFILE,LOCK_UN); + $lock = 0; + } else { + # Failed to get the immediate lock. + + &Apache::lonnet::logthis('WARNING: '. + 'Could not obtain lock to tie coursemap hash '.$fn.'.db for '.$uri.'.'); + } + } + close(LOCKFILE); + unless (($errtext eq '') || ($env{'request.course.uri'} =~ m{^/uploaded/})) { + &Apache::lonmsg::author_res_msg($env{'request.course.uri'}, + $errtext); # TODO: User dependent? } - &Apache::lonmsg::author_res_msg($env{'request.course.uri'},$errtext); # ------------------------------------------------- Check for critical messages +# Depends on user must parameterize this as well..or separate as this is: +# more part of determining what someone sees on entering a course? + my @what=&Apache::lonnet::dump('critical',$env{'user.domain'}, $env{'user.name'}); if ($what[0]) { @@ -778,6 +1197,112 @@ sub readmap { return ($retfurl,$errtext); } +# +# This sub is called when the course hash and the param hash have been tied and +# their lock file is held. +# Parameters: +# $uri - URI that identifies the course. +# $fn - The base path/filename of the files that make up the context +# being built. +# $short - Short course name. +# $cenvref - Reference to the course environment hash returned by +# Apache::lonnet::coursedescription +# +# Assumptions: +# The globals +# %hash, %paramhash are tied to their gdbm files and we hold the lock on them. +# +sub build_tmp_hashes { + my ($uri,$fn,$short,$cenvref) = @_; + + unless(ref($cenvref) eq 'HASH') { + return; + } + my %cenv = %{$cenvref}; + my $gotstate = 0; + %hash=(); # empty the global course and parameter hashes. + %parmhash=(); + $errtext=''; # No error messages yet. + $pc=0; + &clear_mapalias_count(); + &processversionfile(%cenv); + my $furi=&Apache::lonnet::clutter($uri); + # + # the map staring points. + # + $hash{'src_0.0'}=&versiontrack($furi); + $hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title'); + $hash{'ids_'.$furi}='0.0'; + $hash{'is_map_0.0'}=1; + &loadmap($uri,'0.0'); + if (defined($hash{'map_start_'.$uri})) { + &Apache::lonnet::appenv({"request.course.id" => $short, + "request.course.fn" => $fn, + "request.course.uri" => $uri}); + $env{'request.course.id'}=$short; + &traceroute('0',$hash{'map_start_'.$uri},'&'); + &accinit($uri,$short,$fn); + &hiddenurls(); + } + $errtext .= &get_mapalias_errors(); +# ------------------------------------------------------- Put versions into src + foreach my $key (keys(%hash)) { + if ($key=~/^src_/) { + $hash{$key}=&putinversion($hash{$key}); + } elsif ($key =~ /^(map_(?:start|finish|pc)_)(.*)/) { + my ($type, $url) = ($1,$2); + my $value = $hash{$key}; + $hash{$type.&putinversion($url)}=$value; + } + } +# ---------------------------------------------------------------- Encrypt URLs + foreach my $id (keys(%encurl)) { +# $hash{'src_'.$id}=&Apache::lonenc::encrypted($hash{'src_'.$id}); + $hash{'encrypted_'.$id}=1; + } +# ----------------------------------------------- Close hashes to finally store +# --------------------------------- Routine must pass this point, no early outs + $hash{'first_rid'}=$retfrid; + my ($mapid,$resid)=split(/\./,$retfrid); + $hash{'first_mapurl'}=$hash{'map_id_'.$mapid}; + my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$hash{'src_'.$retfrid}); + $retfurl=&add_get_param($hash{'src_'.$retfrid},{ 'symb' => $symb }); + if ($hash{'encrypted_'.$retfrid}) { + $retfurl=&Apache::lonenc::encrypted($retfurl,(&Apache::lonnet::allowed('adv') ne 'F')); + } + $hash{'first_url'}=$retfurl; +# ---------------------------------------------------- Store away initial state + { + my $cfh; + if (open($cfh,">$fn.state")) { + print $cfh join("\n",@cond); + $gotstate = 1; + } else { + &Apache::lonnet::logthis("WARNING: ". + "Could not write statemap $fn for $uri."); + } + } + return $gotstate; +} + +sub unlink_tmpfiles { + my ($fn) = @_; + my $file_dir = dirname($fn); + + if ($fn eq LONCAPA::tempdir()) { + my @files = qw (.db _symb.db .state _parms.db); + foreach my $file (@files) { + if (-e $fn.$file) { + unless (unlink($fn.$file)) { + &Apache::lonnet::logthis("WARNING: ". + "Could not unlink ".$fn.$file.""); + } + } + } + } + return; +} + # ------------------------------------------------------- Evaluate state string sub evalstate { @@ -818,6 +1343,9 @@ sub evalstate { return $state; } +# This block seems to have code to manage/detect doubly defined +# aliases in maps. + { my %mapalias_cache; sub count_mapalias { @@ -877,37 +1405,33 @@ of course for user. This is part of the LearningOnline Network with CAPA project described at http://www.lon-capa.org. -=head1 HANDLER SUBROUTINE - -There is no handler subroutine. - -=head1 OTHER SUBROUTINES +=head1 SUBROUTINES -=over 4 +=over -=item * +=item loadmap() -loadmap() : Loads map from disk +Loads map from disk -=item * +=item simplify() -simplify() : Simplify expression +Simplify expression -=item * +=item traceroute() -traceroute() : Build condition hash +Build condition hash -=item * +=item accinit() -accinit() : Cascading conditions, quick access, parameters +Cascading conditions, quick access, parameters -=item * +=item readmap() -readmap() : Read map and all submaps +Read map and all submaps -=item * +=item evalstate() -evalstate() : Evaluate state string +Evaluate state string =back